US3885623A

US3885623A - Underwater wellhead foundation assembly

Info

Publication number: US3885623A
Application number: US194367A
Authority: US
Inventors: Bruce J Watkins; Glenn D Johnson
Original assignee: Shell Oil Co
Current assignee: Shell USA Inc
Priority date: 1962-05-14
Filing date: 1962-05-14
Publication date: 1975-05-27
Anticipated expiration: 1992-05-27
Also published as: GB959174A

Abstract

An oil or gas well landing base for use with a well conductor pipe in offshore drilling operations conducted in underwater formations from a floating vessel. The base member and the conductor pipe are interconnected by means of a universal joint whereby the conductor pipe maintains substantial vertical alignment irrespective of the slope of the formation on which the base is landed.

Description

United States Patent [1 1 [111 3,885,623

Watkins et al. May 27, 1975 [54] UNDERWATER WELLHEAD FOUNDATION 2,556,384 6/1951 Zeitz 166/75 X 2,606,003 8/1952 McNeill ASSEMBLY 2,659,439 1 H1953 Baker [75] Inventors: Bruce J. Watkins, West Covma; 2,923,531 2 19 0 Bauer et 1,

Glenn D. Johnson, Downey, both of 2,988,144 6/1961 Conrad Calif. 3,143,172 8/1964 Wakefield, Jr 166/.5

[73] Assignee: Shell Oil Company, Houston, Tex.

[22] Filed: May 14, 1962 Primary Exanliner-Ernest R. Purser [21] Appl. No.: 194,367 [57] ABSTRACT An oil or gas well landing base for use with a well con- 52 US. Cl 166/.5; 175/7 ducwr P p in Offshore drilling Operations conducted [51] Int. Cl E21b 7/12 in underwater formations from a floating Vessel The [58] Field of Search 166/665, 75, 85, 96, .5, base member and the o duetor pipe are intercon- 166/ 6; 175/7, 5; 5 42 143 261 nected by means of a universal joint whereby the conductor pipe maintains substantial vertical alignment 5 References Cited irrespective of the slope of the formation on which the UNITED STATES PATENTS base landed- 2,476,309 7/1949 Lang 175/8 16 Claims, 3 Drawing Figures 38 vi v ,t 1, 45 as PATH-HEB MAY 2 7 I975 FIG. 2

FIG. 3

INVENTORS:

BRUCE J. WATKINS GLENN D. JOHNSON FIG.|

THEIR AGENT UNDERWATER WELLI-IEAD FOUNDATION ASSEMBLY This invention relates to underwater wellheads and pertains more particularly to a well foundation assembly or well base which aids in supporting a wellhead on the ocean floor.

A recent development in the oil industry is the drilling and producing of off-shore wells wherein the wellhead assembly and production flow lines are positioned below the surface of the water, preferably on or near the ocean floor so as not to be subjected to the major wind and wave forces and to be out of the way of boats that may navigate in the area. Most off-shore well drilling operations of this type are conducted from a platform or anchored barge from which the various pieces of equipment, used in or on the well, are lowered through the water from the barge to their position near the ocean floor. When operating at water depths or cations where a diver cannot be employed to assemble the equipment on the ocean floor, it is necessary to provide apparatus that may be lowered through the water from a remote vessel, and then aligned and connected to other pieces of equipment at the ocean floor.

When drilling wells on land, the drill site is normally leveled with a bulldozer prior to setting up the equipment and drilling the well. The earth around most land wells is relatively compact so that the weight of the wellhead can be readily supported on this conductor pipe or outermost casing string which is run into the well a few hundred feet and then cemented therein. However, in drilling at off-shore locations, the ocean floor may be relatively soft and does not possess the bearing qualities that compact land formations have.

Thus, in drilling underwater wells and installing equipment at the top of the well by the method described in U.S. Pat. No. 3,256,936, it has become a practice to employ a foundation pad or support plate which is secured to the conductor pile or outermost casing of the well to aid in supporting the casing in a fixed position on the ocean floor at least during the early part of the drilling operations. If the ocean floor at the underwater well location could be leveled prior to the start of drilling operations, the foundation support assembly for the conductor pipe could be in the form of a large flange secured to the outside of the conductor pipe a predetermined distance, say from 5 to 50 feet below the top thereof. With the flange being several times wider than the diameter of the well, it would sit on the ocean floor while the conductor pipe or casing was suspended in the well.

Since the ocean floor at most underwater well drilling locations may slope at any angle, it is the primary object of the present invention to provide a well foundation support assembly for a wellhead and its conductor pipe, which assembly is adapted to move relative to the conductor pipe and assume the angle of the ocean floor at the underwater well location while the conductor pipe remains vertical.

A further object of the present invention is to provide a reinforced underwater wellhead foundation which is adapted to withstand the forces encountered and support the heavy drilling equipment employed in drilling underwater wells.

These and other objects of this invention will be understood from the following description taken with reference to the drawing, wherein:

FIG. 1 is a diagrammatic view taken in longitudinal projection illustrating an underwater well being drilled through the well foundation assembly of the present invention from a drilling vessel positioned on the surface of a body of water;

FIG. 2 is a diagrammatic view taken in partial crosssection of the connection between the conductor pipe and the support base illustrated in FIG. 1;

FIG. 3 is a longitudinal view taken in partial crosssection of one form of the top of a well foundation assembly of the present invention.

Referring to FIG. 1 of the drawing, a drilling platform or vessel 11, or any suitable floatable type is illustrated as floating on the surface of a body of water 12 and as being substantially fixedly positioned over a preselected drilling location by suitable barge positioning means or by being anchored to the ocean floor 13 by suitable anchors (not shown) connected to the anchor lines 14 and 15. Equipment of this type may be used when carrying on well drilling operations in water depths varying from to 1500 feet or more. The drilling vessel is equipped with a suitable derrick 16 as well as other auxiliary equipment needed during the drilling of a well. The derrick 16 is positioned-over a drilling slot or well 18 which extends vertically through the barge in a conventional manner. When using the equipment of the present invention the slot from the barge 18 may be either centrally located or extend in from one edge. However, drilling operations may be carried out over the side of the barge or vessel without the use of a slot. Additionally, it is to be understood that the equipment of the present invention may be also used when drilling a well from any suitable operational base positioned above the surface of the water, such for example, as from a drilling barge having feet extending to the ocean floor or from a platform permanently positioned on the ocean floor.

In FIG. 1 the drilling of a well 19 is shown in progress with a drill-pipe or string 20 extending from the vessel 11 into the well where a bit 21, secured to the lower end of the drill string 20, is rotated to cut the hole deeper. Prior to employing bit 21, a larger diameter bit was used to drill the well 19 down to a point 22. Subsequently, the conductor pipe or foundation pile or outermost casing string 23 was stripped down over the drill string into the well, to its position shown, until the support base 24 of the foundation assembly 25 came to rest on the sloping ocean floor 13. A series of

centralizers

26, 27, and 28 carried on the outside of the conductor pipe 23 and spaced in relation to each other center the conductor pipe in the well 19. Cement slurry was then pumped out through the drill string 20 or a cementing string into the conductor pipe 23 and out the bottom thereof so the cement flowed up the annular space 30 between the conductor pipe 23 and the wall of the well 19, thus forming a rigid foundation under the support base 24 of the foundation assembly 25 and,

around pipe 23.

Thereafter, drilling operations were continued in the well 19 with the smaller bit 21 being attached to the drill pipe 20 and being rotated in the well. At the time the conductor pipe 23 was lowered into the well 19 so that the support base 24 contacted the sloping surface of the ocean floor 13, the support base 24 tilted on its gimbaled joint 32 to the angle of the ocean floor 13 while the axis of the conductor pipe 23 remained vertical, or substantially vertical.

As shown in FIG. 2, the preferred form of the gimbaled joint 32 of the present invention is essentially a ball-and-socket joint interconnecting the conductor pipe 23 and the support base 24. The support base 24 may be of any suitable design and shape and its size would depend to some extent upon the bearing qualities of the soil around the well and the weight to be supported on the base. The base 24 may be, for example, foot in diameter and be constructed of 8-inch I- beams arranged in open grill work. If desired, the top of the support base 24 may be covered with steel plate to give it a better bearing area and to keep cement away from the gimbaled joint 32. However, since the gimbaled joint 32 is generally in its final position prior to the cementing of the conductor pipe 23 and the well, the plate covering the top or bottom of the support base may be omitted if desired.

The support base 24 is provided with a vertical opening through the center thereof in which a steel ring 33 or other support member of members isvertically positioned and welded or otherwise secured to the support base 24. Reinforcing plates or gussets 34 may extend radially from the ring member 33, being welded to the ring member 33 and the support base 24. Fixedly secured to the interior wall of the lower portion of the ring 33 is a bearing member 35 which may be in the form of a plurality of bearing pads or a continuous ring member, preferably made of cast steel. The inner surface 36 of the bearing number 35 is preferably concave in form to conform with the curving outer surface of the sphere or ball 37. Actually, since the conductor pipe 23 and a vertical cylindrical housing member 38 extend either through or into the ball 37, only a partial ball remains to move slidably on the bearing member 35. The ball or alignable bearing means 37 is welded to the conductor pipe 23 at 40 and to the housing 38 at point 41, while the housing in turn is closed at its lower end by plate 42 and welded at points 43 and 44. It is to be understood that the use of a housing 38 to reinforce the conductor pipe 23 above a ball 37 is not essential and may be omitted so that the upper end of the ball would then be welded to the conductor pipe 23 also.

Suitable hold-down devices, which may be in the form of clips 45, are connected to the ring 33 in a suitable manner, as by bolts 46. The inner surface 47 of the clips bear against the outer surface of the ball 37 and prevent the ball 37 from lifting out of the ring element 33. The clips 45 and the bearing members 35 form movement-limiting means carried between the support base and the pipe for preventing substantial axial movement therebetween. At one point in the operation of the well it is necessary to circulate fluid up the conductor pipe and through the wall thereof just above the ball. For this purpose, a nipple 49 extends through the conductor pipe 23 of the housing member 38 with a coupling 48 being provided at the outer end whereby a flexible hose 50 or a rigid pipe 51 (FIG. 1)

may be connected.

For one particular well, the conductor pipe is 20 inches in diameter while the housing member 38 is about 3 feet in diameter. The annular space 52 between the conductor pipe 23 and the housing cylinder 38 may be filled with cement prior to installation in order to reinforce the entire foundation assembly.

As shown in FIG. 3 one or more equipment tracks 53 may be supported on ribs or gussets 54 which are welded to the outside of the housing cylinder 38. The

upper end of the conductor pipe 23 maybe provided with a landing surface 55 for hanging a string of pipe therein or for any other suitable purpose. Additionally, an annular plate 56 is welded between the housing 38. and the upper end of the conductor pipe 23 to reinforce the structure. A well casing head 57 or other piece of well equipment used in the drilling or production of a well may be seated in the top of the conductor pipe 23 and fixedly secured therein by suitable connector means, as by bolts 58.

Although a self-adjusting well foundation assembly or base member has been described hereinabove with regard to using a ball and socket arrangement of a gimbaled joint, it is to be understood that any other suitable type of weight supporting flexible joint may be employed between a support pad or base surrounding a conductor pile and the outside of the conductor pile.

tend into a well with a portion thereof positioned above the formation to form the outermost pipe of a well assembly,

2. support base means connected to and surrounding said pipe and radially extending therefrom when is normal to the pipe axis, said support base means being larger than the diameter of the well at the top thereof, and I j 3. weight supporting flexible joint means interconnecting said support base means to said I pipe whereby said support base means is adapted to be seated on and conform to a sloping formation adjacent a substantially vertical well in which said pipe is adapted to be positioned, and movement-limiting means carried between said support base means and said pipe for preventing substantial axial movement therebetween.

2. The apparatus of claim 1 wherein said weight supporting flexible joint means is a ball-and-socket joint,

3. The apparatus of claim 2 wherein the ball-andsocket joint comprises a partial ball element affixed to the'outside of the pipe, and a ball-receiving socket element substantially centrally mounted in an opening in.

the support base means.

4. The apparatus of claim 1 including centralizer means mounted on the outside of said pipe below said weight supporting flexible joint means for centering the pipe in a well.

5. The apparatus of claim 4 wherein said centralizer means comprise a plurality of centralizers secured at spaced intervals on the outside of said pipe.

6. the apparatus of claim 1 including pipe hanging means carried near the top of said pipe for hanging at least one pipe string within said pipe.

7. The apparatus of claim 1 includingjseatingand connector means carried at the top of said pipe for seating and securing a casinghead thereon.

8. The apparatus of claim I including a cylindrical housing mounted concentrically 0n the upper end of said pipe in spaced relationship theretoformi ng an annular space therebetween, and support means connecting the upper and lower ends of said housing to the pipe.

9. The apparatus of claim 8 wherein said annular space is filled with cement.

10. The apparatus of claim 1 wherein said support base means is made of elongated structural members connected together in the form of an open grid having a centrally located hole therein of a size to permit said pipe to pass therethrough, one portion of said weight supporting flexible joint means being affixed to said support base means adjacent and surrounding said hole.

11. A well foundation assembly for use in a well drilled in a formation covered by a body of water, said assembly comprising a large-diameter elongated pipe of a length to extend into a well with a portion thereof positioned above the formation to form the outermost pipe of a well assembly,

support base means operatively connected to and surrounding said pipe and radially extending therefrom when it is normal to the pipe axis, said support base means being larger than the diameter of the well at the top thereof, and

weight-supporting flexible joint means in operative engagement between said support base means and said pipe whereby said support base means is adapted to be seated on and conform to a sloping formation adjacent a substantially vertical well in which said pipe is adapted to be positioned,

said weight-supporting flexible joint means comprising a bearing portion on said support base means and an alignable bearing means seated in movable sliding engagement with said bearing portion of said support base means,

said alignable bearing means, when taken in vertical section, having a downwardly and inwardly curving outer surface at least on the lower portion thereof which is in contact with said bearing portion on said support base means.

12. Landing base apparatus for use with a conductor pipe in off-shore drilling operations conducted in an underwater formation from a floating vessel, comprising in combination: a base member adapted to land on said formation, said base member including means for supporting said conductor in said formation and means associated with said conductor pipe so arranged and proportioned that said conductor pipe is universally movable relative to said base member whereby said conductor pipe maintains substantially vertical alignment irrespective of the slope of said formation on which said base member is landed.

13. The apparatus of claim 12 including means for' fixing said conductor pipe relative to said formation in said substantially vertical alignment.

l4. Landing base apparatus for use in off-shore drilling operations conducted in an underwater formation from a floating vessel with conductor pipe extending through said apparatus into said formation, comprising in combination: a base member having a downwardly tapered opening forming a socket therein and adapted to land on said formation and receive said conductor pipe extending therethrough into said formation, a rounded enlargement on said conductor pipe near the upper end thereof said enlargement being so arranged and proportioned as to seat in said tapered opening, and whereby said conductor pipe is universally movable relative to said base member so that said conductor pipe maintains substantially vertical alignment irrespective of the slope of said formation on which said base member is landed.

15. Landing base apparatus for use in off-shore drilling operations conducted in an underwater formation from a floating vessel with conductor pipe extending through said apparatus into said formation, comprising in combination: a base member having a downwardly tapered opening forming a socket therein and adapted to land on said formation and receive said conductor pipe extending therethrough into said formation, a rounded enlargement on said conductor pipe near the upper end thereof said enlargement being so arranged and proportioned as to seat in said tapered opening whereby said base member supports said conductor pipe in said formation, said conductor pipe being universally movable relative to said base member whereby said conductor pipe maintains substantially vertical alignment irrespective of the slope of said formation on which said base member is landed, and means affixed to said base member for retaining said rounded enlargement in said tapered socket.

16. Landing base apparatus for use in off-shore drilling operations conducted in an underwater formation from a floating vessel with conductor pipe extending through said apparatus into said formation, comprising in combination: a base member having a downwardly tapered opening forming a socket therein and adapted to land on said formation and receive said conductor pipe extending therethrough into said formation, a rounded enlargement on said conductor pipe near the upper end thereof said enlargement being so arranged and proportioned as to seat in said tapered opening whereby said base member supports said conductor pipe in said formation, said conductor pipe being universally movable relative to said base member whereby said conductor pipe maintains substantially vertical alignment irrespective of the slope of said formation on which said base member is landed, and means for limiting longitudinal movement of said base member with respect to said conductor pipe whereby said base member may be lowered from said vessel with said conductor pipe.

Claims

1. A well foundation assembly for use in a well drilled in a formation covered by a body of water, said assembly comprising

1. a large diameter elongated pipe of a length to extend into a well with a portion thereof positioned above the formation to form the outermost pipe of a well assembly,

2. support base means connected to and surrounding said pipe and radially extending therefrom when it is normal to the pipe axis, said support base means being larger than the diameter of the well at the top thereof, and

2. The apparatus of claim 1 wherein said weight supporting flexible joint means is a ball-and-socket joint.

3. The apparatus of claim 2 wherein the ball-and-socket joint comprises a partial ball element affixed to the outside of the pipe, and a ball-receiving socket element substantially centrally mounted in an opening in the support base means.

3. weight supporting flexible joint means interconnecting said support base means to said pipe whereby said support base means is adapted to be seated on and conform to a sloping formation adjacent a substantially vertical well in which said pipe is adapted to be positioned, and movement-limiting means carried between said support base means and said pipe for preventing substantial axial movement therebetween.

7. The apparatus of claim 1 including seating and connector means carried at the top of said pipe for seating and securing a casinghead thereon.

8. The apparatus of claim 1 including a cylindrical housing mounted concentrically on the upper end of said pipe in spaced relationship thereto forming an annular space therebetween, and support means connecting the upper and lower ends of said housing to the pipe.

9. The apparatus of claim 8 wherein said annular space is filled with cement.

11. A well foundation assembly for use in a well drilled in a formation covered by a body of water, said assembly comprising a large-diameter elongated pipe of a length to extend into a well with a portion thereof positioned above the formation to form the outermost pipe of a well assembly, support base means operatively connected to and surrounding said pipe and radially extending therefrom when it is normal to the pipe axis, said support base means being larger than the diameter of the well at the top thereof, and weight-supporting flexible joint means in operative engagement between said support base means and said pipe whereby said support base means is adapted to be seated on and conform to a sloping formatioN adjacent a substantially vertical well in which said pipe is adapted to be positioned, said weight-supporting flexible joint means comprising a bearing portion on said support base means and an alignable bearing means seated in movable sliding engagement with said bearing portion of said support base means, said alignable bearing means, when taken in vertical section, having a downwardly and inwardly curving outer surface at least on the lower portion thereof which is in contact with said bearing portion on said support base means.

12. Landing base apparatus for use with a conductor pipe in offshore drilling operations conducted in an underwater formation from a floating vessel, comprising in combination: a base member adapted to land on said formation, said base member including means for supporting said conductor in said formation and means associated with said conductor pipe so arranged and proportioned that said conductor pipe is universally movable relative to said base member whereby said conductor pipe maintains substantially vertical alignment irrespective of the slope of said formation on which said base member is landed.

13. The apparatus of claim 12 including means for fixing said conductor pipe relative to said formation in said substantially vertical alignment.

14. Landing base apparatus for use in off-shore drilling operations conducted in an underwater formation from a floating vessel with conductor pipe extending through said apparatus into said formation, comprising in combination: a base member having a downwardly tapered opening forming a socket therein and adapted to land on said formation and receive said conductor pipe extending therethrough into said formation, a rounded enlargement on said conductor pipe near the upper end thereof said enlargement being so arranged and proportioned as to seat in said tapered opening, and whereby said conductor pipe is universally movable relative to said base member so that said conductor pipe maintains substantially vertical alignment irrespective of the slope of said formation on which said base member is landed.